1. Field of the Invention
The present invention relates to a photo-electric transducer adoptable in various image data processing apparatus such as a facsimile transmitter-receiver, a character reader and a copying machine.
2. Description of the Prior Art
Image sensors which have previously been known and most widely used in the above mentioned apparatus are one-dimensional photodiode type long sensors manufactured using crystalline silicon. However, such conventional sensors have some disadvantages. First, the available size of single crystal is limited; also the available machining technique has many limitations. Therefore, the length of photo-reception part of the sensor is greatly limited. Secondly, the sensor can be manufactured only with low yield.
The limited length of the photo-reception part of the known sensor brings forth various drawbacks. For example, when an original of A4 format of 210 mm in width is to be read using such sensor, it has been required conventionally to use a lens system through which the original is focused on the photo-reception surface of the sensor as a minified image. This method of reading employing an optical lens system is, of course, undesirable because it is contrary to the general desire to miniatuarize the photosensor apparatus as a whole. Further, since it is impossible to increase the area of the individual photo-receptor elements, a large quantity of light is required to obtain a sufficiently large output signal from the input signal. Because of these limitations, such photosensors, have previously been adopted only in those apparatus which can spare a long time for reading and therefore operate at relatively low speed or in those applications for which high resolving power is not required.